Sustainable energy evolution: unveiling thermal decomposition kinetics in biomass co-generation

The energy generation from biomass wastes necessitates understanding the kinetics and mechanisms of thermal decomposition to optimize reactor design and efficiency. However, the decomposition of biomass, which comprises hemicellulose, cellulose, and lignin, poses analytical challenges. This study focuses on the thermal decomposition of sugarcane bagasse, a common biomass used for energy co-generation. Thermal analysis performed using thermogravimetric/differential thermal analysis in an argon atmosphere at varying heating rates (2, 5, and 30 K/min) revealed key insights into its decomposition mechanisms. The overall reaction exhibited three distinct peaks in the derivative thermogravimetry (DTG) curve, corresponding to the decomposition of hemicellulose, cellulose, and lignin. Gaussian deconvolution was employed to separate these peaks, followed by analysis using various nonisothermal kinetic methods. Integral methods revealed two decomposition stages but presented challenges in selecting precise reaction models. These challenges were mitigated by separating the reactions into their components. The reaction order model f(α) = (1 − α)1.5 effectively described the decomposition kinetics. Activation energy values ranged from 120 to 280 kJ/mol for the overall reaction, with specific values of 200–280 kJ/mol for hemicellulose, 280–350 kJ/mol for cellulose, and 40–150 kJ/mol for lignin. Nonlinear least square minimization refined these values, showing better fitting in reconstructed dα/dT plots.